If I measure my waist comfortably right around my bellybutton it's about 34.5 inches.

The belts I'm looking at come in:
Medium: 27"-32"
Large: 33" - 38"

If I were to measure my waist the way I would wear a belt (tight and cinched down) I would probably hit around 32 or a little under. So should I get the medium? Or do they take this into account and I should get the large?

I guess the question is, when you measure yourself are you supposed to take a relaxed measurement or are you supposed to measure tight, the way you would wear the belt?